Generally bell sound and vibration are well used for the receipt of communication device. For the vibration, it is a general case that a whole device is able to vibrate by actuating a small vibration generation device and subsequently transferring an actuating force to a case of the device.
Currently, the vibration generation device which is one of the receipt means applied in the communication device such as a cell phone is a component converting electric energy into mechanical vibration by using the generating principle of electromagnetic force and the vibration generation device is installed in a cell phone and is used for silent notice of the receipt.
The vibration generation device is widely used for the purpose of the notice of receipt of the cell phone or the like, and recently the use of vibration generation device is increased as follows, the vibration generation device is installed in a game device in order to inform user thereof of the game progress conditions or the vibration generation device is installed in a touch phone or the like in order for user thereof to know feeling that keys thereof were touched.
The need for product development of a new structure is rising which the drawback of the existing product of the vibration generation device is avoided and its quality is dramatically improved in the state expecting miniaturization and high qualification of the cell phone component following the trend that the cell phone market has been quickly expanded and moreover multi-functions are added to the cell phone.
The vibration generation device of the related art mounted on the portable terminal as a vibration generation device basically using the primary vibration system attaches a weight to an elastic body such as a coil spring and has a coil to vibrate the weight.
The weight vibrates depending on the frequency response characteristics predetermined by the weight and a modulus of elasticity of the elastic body when current is applied to the coil.
As described above, recently the portable terminal launched has a function providing feedback which corresponds to input to user, by outputting voice or vibration response to the user's touch input.
Particularly, in case of the portable terminal applied a haptic technology, the research about the vibration generation device generating the various types of vibrations in order to provide a various of haptic feedback in response to user's various input is underway.
The vibration generation device of the related art, however, generates a vertical actuating power of the weight using Lorentz force between a coil and a fixed magnet, wherein it is difficult to get good characteristics in vibration strength, vibration frequency band width, or the like because of limitation of a structure of the vibration generation device by means of Lorentz force.
Particularly, in the vibration generation device of LRA (Linear Resonant Actuator) method of the related art, there was a problem that the response speed is not fast because there is a limit to the increase in damping value.